Electron discharge device of the magnetron type



June 21, 1949 P. 1.. SPENCER ELECTRON DISCHARGE DEVICE OF THE MAGNETRONTYPE Filed Nov. 15, 1943 2 Sheets-Sheet 1 Ju ne 21, 1949. P. L. SPENCERELECTRON DISCHARGE DEVICE OF THE MAGEETRON IYPE 2 Sheets-Sheet 2 FiledNov. 15, 1945 INVENTOR, Pmcy A. 5Pzwcae, I @g:

Patented June 21, 1949 ELECTRON'DISCHARGE DEVICE OF"THE MAGNETRON- TYPEPercy.;L.--. Spencer, West NeWtIl'}fMa,$S.-,: assignor; to ltaytheonManufacturing Company, Newton. Mass. ;..a.-corporation of DelawareApplication November 15, 19%; Serial No-5510A24 4Glaims..; (CL. 3151--40) Y This invention relates to a.mag-netron,--.and more particularlyto one of .thei-multiple anode type in whichtheinternal.structure-provides a plurality of oscillating;circuitspall;of whichare intended to oscillate at .thessame frequencyand thus to contribute tothe efiective .output'of the magnetron.countered in coupling-all. of the; oscillating circuits together, andpropagating the-oscillatory energy from circuittocircuituntilit ispicked up by the output connection..-

An object of this invention is to devise. anarrangement in which. thecoupling. between the oscillating portion of the device and the outputmeans is substantially increased.

Another object istopdevise; an arrangement of the above typeinwhichtheefficiency thereof is substantially increased:

The foregoing and .other vention will be best ,.understood vfrom thefollowing description. of .exemplifications; thereof, reference beinghad-to:theaccompanying drawings, wherein:

Fig. 1 is a longitudinal cross-section of a magnetron embodying myinvention taken alongv line l-i of Fig. 2;

Fig. 2 is a transverse crossrsectionitak i g line 2-2 of Fig. 1;

Fig. 3 is a, longitudinalcross-section of another embodiment ofmyinvention taken :along line 33 of Fig. 4; and J Fig. 4 is a transversecross-.sectiontaken along line 5-4 of Fig. 3.

The magnetronillustrated in Figs. '1 and 2 comprises a tubular envelopel madeuof a cylinder of conducting-materialpsuch-as copper. The ends ofthe envelope are oovered by caps 2 and 3 likewise formed of conductingmaterial, such as copper, andhermetically soldered in place on the endsof the envelope I. The en velope I is iormedwithacentralxannularzprojection 4. Extending from :substantially. the centralportion of the projection, 4 is a central ring-shaped plate 5 to theinner face rality of radial plates .6 are arranged above the plate 5 andsolderedinplacey-along the-*z ortion of the inner surface of theprojection. 4. ;A similar lower set of radial plates ;1 is soldered inplace along the lower :portiomof the-. inner surface of the projection-4below the ring 5. The plates 6 and 1; are.preierably aligned with eachother, and may bestamped out of a sheet of highly-conductivecopper...The.- inner end of the plate 5- and the mncrwcnds oi theplates. 6

Heretofore adifficulty. has been en-.

bjects of this in soldered along its outer edge of the projection 4. .Aplu- 2 and I form anode facestwhichrcooperate with-a cathode --8supported substantiallyx centrally t of. said anode faces. of theindirectly+heated oxide-coated thermi.-.. oniotype having an outerconducting: cylinder} coated with electron-emissive oxides, and= havingan internal heater, the end. conductors-8 and iii of whichproject.fromwtheopposite ends of the cathode structure -8. One oflthe.conductors 9 may be electrically connected tosthe external cathodesleeve while the other conductor .10 is insulated from said sleeve. .Thecathode 8 is supported by a pair of lead-inconcluctor It.

welded respectively .to the end conductors ll and Ill. The lead-inconductors! I pass through glass seals l2 mounted at the outer-:endsofconduct.-

ing pipes l3 hermetically fastenedwthrough the wall of the envelope ladjacentthe .uppenand.

lower ends thereof.

' When such a magnetron isplaced betweensuitable magnetic. poles [4 tocreate a longitudi.- nal magnetic field and the device is ener ized,oscillations are set up with the. opening between each pair of plates 6operating asa tuned. oscillating cavity. These oscillations may. be. ledout from the tube by'means of a coupling. loop I5.extending into anopening iormed'in the ring 5. One end of the coupling loop 15 is con--nected to the inner end of a conducting pipe .11- hermetically sealedthroughthawall of the en.'

through which the high frequency oscillationsgenerated by the. magnetronmay, .be' connected to a suitable utilization circuit.

Heretofore in magnetrons of the multiple anode type havin radial arms,the couplingto the. output loop has been relatively-weak due to.

the fact that the oscillating-energy had to be propagated throughout thelength'of each os-. cillating cavity or opening-and .from cavity tocavity until the coupling loop was reached. Shortening of the-radialarmswould shorten the path through. which the oscillatory. energyistransmitted to the.coupling..1oop.-.However, such shortened armsv would.reduce the. effective elece .lengthbelow. that at which the emission.froma sufficiently large tron-receiving. anode, face c th dea e The:cathode:.8 is :preferably;

The other end ofthecouplingloop.

An additional conducting pipe; not shown,,

w s .ut zed to .hand citheia ount.

of power desired. By the present arrangement the advantage of ashortened coupling path is obtained without substantially decreasing theeffective current-carrying capacity of the tube. It will be noted thatin the above construction, the previous anode plates have been in efiectdivided into two halves 6 and 7, with the ring interposed therebetween.It will be noted that an annular space 20 exists between the ring 5 andthe plates 6, and a similar annular space 2| exists between the ring 5and the plates 1. The coupling loop i5 is sufficiently large so that itis coupled to both of said annular spaces 20 and 2i. The device ineffect consists of two oscillating magnetron structures operating inparallel. Each of these structures possesses the desired shortenedlength of anode arm and both together operate to deliver substantiallythe same amount of power as in the previous construction. Since the loopi5 is coupled to each of the two structures, these structures arecoupled together, thus tending to oscillate in synchronism andcontribute to the output of the tube. The shortened coupling pathincreases the coupling which exists between the loop I 5 and each of theoscillatin cavities. Tubes con structed as above therefore tend to be ofa substantially increased efficiency.

In some instances it may be desirable to increase the degree to whichthe two magnetron structures within the tube are coupled or tiedtogether more strongly. An alternative construction in which suchincreased coupling occurs is shown, for example, in Figs. 3 and 4. Inthese figures the same reference numerals which are used in Figs. 1 and2 are applied where the elements are identical. The cross-section takenin 4 being somewhat different from that of Fig. 2, the heater 22 of thecathode 3 appears in Fig. 4. The anode elements of Figs. 1 and 2 arereplaced by radial plates 23 soldered in place along the inner surfaceof the projection ti. Each of the plates 23 is formed wi h asubstantially central opening 2 1. These openings are preferably locatedat the rear of each of the plates 23, leaving a continuously-conductinganode face extending the total length of the plate 23 and presented tothe cathode #0. It will be seen that in this arrangement two magnetronstructures likewise exist as in Figs. 1 and 2. In Figs. 3 and 4,however, each anode arm of the upper structure is directly electricallyconnected to the corresponding anode arm of the lower structure by thecontinuously-conducting anode face of the plate 23. Such an arrangementhas substantially all of the advantages of the embodiment shown in Figs.1 and 2 with the added advantage of increased coupling between the upperand lower halves of the tube. Such an arrangement likewise tends tooperate with increased efficiency.

Of course it is to be understood that this invention is not limited tothe particular details as described above as many equivalents willsuggest themselves to those skilled in the art. It is accordinglydesired that the appended claims be given a broad interpretationcommensurate with the scope of the invention within the art.

What is claimed is:

1. An electron-discharge device comprising: a cathode; an anodestructure spaced from and surrounding said cathode; said anode structureincluding a plurality of anode arms having electron-receiving facesadjacent said cathode; each of said anode arms being divided into upperand lower sections by a slot passing through its electron-receivingface, along an axis perpendicular to said face; the slots of all of saidanode arms being circularly aligned; and a conducting member supportedintermediate said upper and lower anode arm sections; said conductingmember traversing all of said slots.

2. An electron-discharge device comprising: a cathode; an anodestructure spaced from and surrounding said cathode; said anode structureincluding a plurality of anode arms having electron-receiving facesadjacent said cathode; each of said anode arms being divided into upperand lower sections by a slot passing through its electron-receivingface, along an axis perpendicular to said face; the slots of all of saidanode arms being circularly aligned; a conducting member supportedintermediate said upper and lower anode arm sections; said conductingmember traversing all of said slots; and a coupling device, adapted tobe connected to an external circuit, extending into one of said slotsadjacent said conducting member.

3. An electron-discharge device comprising: a cathode; an anodestructure spaced from and surrounding said cathode; said anode structureincluding a pluality of anode ams having electron-receiving facesadjacent said cathode; each of said anode arms being divided into upperand lower sections by a slot passing through its electron-receivingface, along an axis perpendicular to said face; the slots of all of saidanode arms being circularly aligned; a conducting member supportedintermediate said upper and lower anode arm sections; said conductingmember traversing all of said slots and dividing each of the same intotwo smaller slots; and a coupling device, adapted to be connected to anexternal circuit, extending into both of the smaller slots of at leastone of said anode arms.

4. A magnetron comprising: a cathode; an anode structure spaced from andsurrounding said cathode; means for establishing a magnetic field in thespace between said cathode and said anode structure, in a directionperpendicular to the electron path between said cathode and said anodestructure; said anode structure including a plurality of anode armshaving electron-receiping faces adjacent said cathode; each of saidanode arms being divided into upper and lower sections; the upper andlower sections of all of said anode arms being spaced by circularlyaligned slots; a conducting member supported intermediate said upper andlower sections, and traversing all of said slots; and a coupling device,adapted to be connected to an external circuit, extending into one ofsaid slots adjacent said conducting member.

PERCY L. SPENCER.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 2,233,482 Linder Mar. 4, 1942,247,077 BleWett et al June 24, 1941 2,250,698 Berline July 29, 19412,293,798 Braden Aug. 1942 2,366,555 Ramo Jan. 2, 1945 2,422,028 Martin,Jr. June 10, 1947 FOREIGN PATENTS Number Country Date 215,600Switzerland Oct. 16, 1941 509,102 Great Britain July 11, 1939

